<template>
  <div class="cba">
    <div class="a">红色</div>
    <div class="b">绿色</div>
    <div class="c">蓝色</div>
  </div>
</template>

<style scoped>
.cba {
  display: flex;
  width: 600px;
  height: 200px;
}
.a {
  background-color: red;
  flex-grow: 1;
}
.b {
  background-color: green;
  flex-grow: 1;
}
.c {
  background-color: blue;
  flex-grow: 1;
}
</style>
